Retroreflective articles have the ability to redirect substantial quantities of incident light, which otherwise would be reflected elsewhere, back towards the incident light source. This ability has led to widespread use of retroreflective articles in a variety of applications relating to traffic safety. Retroreflective sheetings are particularly useful to guide motorists under poor lighting conditions, such as, for example, under nighttime driving or under inclement weather. Examples of uses of retroreflective sheeting include, but are not limited to traffic signs, cones, and barricades.
Some skilled in the art have developed various methods of making profiled retroreflective articles using retroreflective base sheets. By "profiled," it is meant that some portion of the retroreflective base sheet is elevated from the body of the article so as to create a vertical component.
For example, Assignee's pending U.S. patent application Ser. No. 08/895,384, filed on Jul. 16, 1997, discloses a retroreflective sheeting that has a continuous, longitudinal extending retroreflective portion and pleated retroreflective portions. Each pleated portion extends generally perpendicular to and is spaced along the longitudinal portions. As defined in the application, "pleated" means that a portion of the sheeting is doubled upon itself and bonded together by, for example, an adhesive or ultrasonic bonding. The pleats elevate a portion of the retroreflective sheet so that incident light at high entrance angles strikes the pleated portion and is retroreflected by the pleated portion. The sheeting is very useful for application on traffic barricades, such as jersey barriers or guard railings.
Publication No. WO 93/21388 discloses a method and device for producing light-reflecting surfaces, particularly for road markings. The markings have ridge-like stripes containing reflecting components, the stripes applied perpendicularly or at an angle to the traffic direction. The marking can be applied directly onto a road surface or prefabricated onto a carrier web and applied to a road surface. When a marker is made directly on the road, the method includes applying a thin coating onto a road surface, applying ridge-like profile markings across the longitudinal direction of the coating, applying light reflecting materials, such as glass beads, into the surfaces of the coating and ridge-like material while the surfaces are still soft to yield a pavement marking.
A need exists for streamlined methods to make profiled retroreflective articles for use in vertical or horizontal applications.